Pulled elbow--not the effect of hypermobility of joints.

A detailed description of pulled elbow is missing from standard orthopaedic text books. Recently it has been reported that the prevalence of hypermobility among children with pulled elbow is higher than that in the normal population and that pulled elbow can be considered to be a consequence of joint hypermobility. Two hundred children with pulled elbow comprising 106 girls and 94 boys (age range 3-84 months, mean age 24 months) were treated and evaluated for signs of hypermobility in a prospective study. Hypermobility of joints was noted in 17 (8.5 per cent) of children who had a pulled elbow while in the 71 children in whom there had been more than one episode, the rate of hypermobility was 8.4 per cent. Comparison of these results with a control group of 100 normal children, in whom 10 (10 per cent) exhibited hypermobility, showed no association between joint hypermobility and an increased incidence of pulled elbow. The anatomical construction of the radial head, relative plasticity of the cartilage and the immature annular ligament in young children possibly predisposes them to pulled elbow, the incidence of which is increasing in our modern physically competitive society where children are participating in a wide range of physically demanding sports activities. Pulled elbows can also occur in children with hypermobility of joints, but there is no evidence that the incidence has increased.